One side effect of the Trump administration’s tariffs on imported goods will be a stronger dollar, which will make U.S. exports more expensive and less competitive abroad. Thing is, those tariffs — along with the administration’s approach to foreign policy — may be starting to have another negative effect on the economy: getting foreign investors to think twice about investing in the U.S.

One of the biggest effects of tariffs is that they make an economy more isolated. Teresa Fort, a professor at the Tuck School of Business at Dartmouth College, said trade barriers cut out foreign competitors, so American companies can take their market share.

“Workers and capital are going to move towards sectors that are probably not what the U.S. is best at doing,” Fort said.

In that case, Fort said that companies’ output would slow down. The lack of competition could make them complacent — even lazy.

“It might take more U.S. workers to make the same things we were making before,” Fort said. “That’s reduced productivity. And that’s going to translate into higher prices and less domestic consumption.”

In other words, slower economic growth. And that would make U.S. companies a less attractive target for investors.

Over the last few weeks, bond markets have been anticipating less growth thanks to the president’s tariffs.

In the short run, investors have been fleeing to safety, per Winnie Cisar, head of strategy at CreditSights.

“When you have people who are expecting slower growth, or even an economic contraction, they will move into asset classes that are viewed as less risky overall, like U.S. treasuries and also the U.S. dollar,” she said.

But Cisar said the president’s tariffs — and all of the uncertainty associated with them — are causing many investors to question even that strategy. Now, she said some are asking themselves whether they want to invest in the United States at all.

“Whether the administration is willing to go far enough to drive kind of a sour sentiment and actual selling of U.S. treasuries is very much an open question,” Cisar said.

Slower economic growth can make U.S. government bonds riskier. Teresa Fort at Dartmouth said if the economy stalls, U.S. debt will grow as a share of GDP, to a point where it starts to become unsustainable.

“And then, that is going to start giving the U.S. stronger and stronger incentives to want to default,” Fort said.

About a third of U.S. government bonds are held by foreign investors, many of them in countries the Trump administration is beefing with.

“Canadians are completely furious about Trump’s remarks that Canada should be a 51st state, and you’ve got these very, very big pension funds in Canada that control a lot of flows into the U.S.,” said Sebastian Mallaby, senior fellow at the Council on Foreign Relations. “And they are subject to political pressure within Canada.”

Meanwhile, President Trump’s decision to distance the U.S. from the European Alliance has caused the German government to ramp up its spending, especially on defense. All of a sudden, Mallaby said the European economy is looking relatively strong.

“This is the first time in as long as most people can remember that global portfolio allocators are saying ‘Hey, this could be the moment to switch your money out of American financial assets, into Europe,’” he said.

If foreign investors start doing that, the effects will ripple throughout the U.S. economy, said Barry Eichengreen, an economics professor at UC Berkeley. For instance, if demand for government bonds starts to fall, the government will have to pay more interest to try to win investors back.

“So that will push up interest rates and borrowing costs across the board,” Eichengreen said.

And Eichengreen said a U.S. economy with less foreign investment is a smaller economy — which would mean less spending and lower incomes for Americans.